This invention relates generally to battery-back up systems for supplying alternating current (“AC”) or direct current (“DC”) power to electrical loads. More particularly, this invention relates to methods and apparatus for collecting information on the status of one or more back-up batteries and communicating the information to the users of uninterruptable power supply (“UPS”) systems.
There are numerous types of UPS systems for supplying backup AC or DC power to a load with batteries or other energy storage devices. The back up power is required when power from an AC power source is performing outside of acceptable limits or fails completely. UPS systems that supply AC power to an AC load, as a back-up to an AC power source, are referred to herein as AC to AC (“AC-AC”) class UPS systems. Those that supply DC power to a DC load, as a back up to an AC power source, are referred to as AC to DC (“AC-DC”) class UPS systems.
Prior art battery back-up systems have used one very high voltage battery pack made up of a number of series connected 12 volt automobile batteries, for example. This battery pack is not very reliable for a power back-up system because the whole battery pack is lost if one of the batteries fails and creates an open circuit. It is known to use parallel coupled battery packs to avoid the foregoing problem but even when one of these battery packs fail it is time consuming to identify the particular one or two or more battery packs that require replacement.
Furthermore, in prior art battery pack back-up systems it has been complicated to collect and process battery pack voltage and charge and discharge currents for evaluating the individual battery packs whether connected in series or parallel.
The present invention overcomes the limitations of prior art battery back-up systems by coupling a digital data processor to one or more batteries or battery packs. The processor is used to gather information about the status of an individual battery pack and report the information to a user by setting off an alarm. The battery pack information is also made available for viewing on an LCD display. In addition, a communication system is created among at least a single battery pack and a main processor associated with the power control circuit of a UPS system.
Accordingly, it is an object of the present invention to employ digital processors with a battery to gather information about the battery including whether it is over heating, needs replacement, is capable of being charged, is at float voltage and whether it is a good battery capable of supplying full power to a load.
Another object of the invention is to identity a battery in a group of batteries that requires replacement by coupling a light emitting or an audio alarm to each battery in the group.
Still another object of the invention is to communicate battery information collected at a battery to a remotely located digital processor such as the processor used in the power control circuit of a UPS system.
It is another object to integrate battery pack information into the computer system administrating a UPS system having battery packs for power back-up.
Yet another object of this invention is to enhance the performance of battery packs in UPS systems used with computer, telephone, process control and other downtime sensitive electrical loads where loss of power means loss of information or service.
Additionally, it is an object to enable a UPS system processor to communicate with a monitor associated with each battery in a group of one or more batteries which are providing back-up power to an electrical load.
Finally, it is an object of the invention, to detect a battery pack among a group of battery packs electrically coupled together that requires service and to notify users in advance of trouble so there is time to service the battery pack, for example, by replacing it with another battery pack.